// 建立到真实服务器的socket
$server_sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
socket_connect($server_sock, "127.0.0.1", $listen_port);
// 建立真实服务器socket和真实客户端socket之间的映射关系
$socket_maps1[$new_client] = $server_sock;
$socket_maps2[$server_sock] = $new_client;
// 添加到select轮询中
$select->add($server_sock);
// $listen_sock的可读数据是因为有新连接，已经处理了。暂时去掉，因为下面开始处理数据转发
//select->remove( $listen_sock );
} else {
// 读取数据，失败则从轮询socket中删除，并关闭socket
$client_data = @socket_read($socket, 1024, PHP_NORMAL_READ);
if ($client_data === false) {
socket_close($socket);
$select->remove($socket);
echo "client disconnected.<br />";
continue;
}
// 如果socket在$socket_maps1的key中，说明是从客户端读到了数据
if (in_array($socket, array_keys($socket_maps1))) {
//echo "readed from client.<br />";
if (!socket_write($socket_maps1[$socket], $client_data)) {
socket_close($socket);
socket_close($socket_maps1[$socket]);
$select->remove($socket);
$select->remove($socket_maps1[$socket]);
print "Write to server error.<br />";
}
print htmlentities($client_data) . "</b><br />";
} elseif (in_array($socket, array_keys($socket_maps2))) {
